Stable offset emulsion inks containing water tolerant emulsion stabilizer

ABSTRACT

A printing ink is disclosed containing: an emulsion stabilizer having a water tolerance value of between more than about 1.0 and equal or less than about 11.0 and water as a dispersed phase, wherein said emulsion stabilizer stabilizes the water to form a stabilized emulsion printing ink.

PRIOR APPLICATIONS

This application claims benefit of the U.S. provisional application Ser.No. 60/853,329, filed Nov. 3, 2006, the contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to a stabilized emulsion printing ink containingan emulsion stabilizer having a water tolerance value of between morethan about 1.0 and equal or less than about 11.0.

BACKGROUND OF THE INVENTION

Historically, lithographic web offset heat set inks contain between 30%and 45% volatile organic compounds (VOC). Besides being detrimental tothe environment, VOCs are also flammable and hazardous to the printerswho operate the press. Thus, it is desirable to reduce the VOC contentin lithographic web offset heat set inks as much as possible. Initialattempts at solving this problem involved the use of chemical reactionsthat were triggered in a press oven. However, such oven cured inksystems did not have shelf stability.

Therefore, a heat setting web offset ink will typically contain thefollowing major components (a) a high molecular weight ink resin todisperse the pigment and also to provide the toughness and gloss the inkrequires on drying, (b) solvents to provide the fluidity to the inkbefore it is placed on the web and dried in an oven, (c) pigment, and(d) other minor components such as gellants, which provide structure tothe ink, plasticizers (non volatile solvents), waxes, thickeners, andantioxidants. Conventional heatset inks set or dry by evaporation of theink oil on heating at 250 to 300° F., and, to some degree, bypenetration of the ink oil into the paper, leaving behind a hardpolymeric film.

EP 731150 and EP 960911 describes rapid thermosetting low VOC web offsetlithographic ink systems comprising solid resin, drying oil alkyds,bodied drying oil, vegetable oil, fatty acids, multifunctionalunsaturated polyester, reducing agents and transition metal salts oforganic acids and may also include an aqueous fountain solutioncontaining peroxides that promote free radical polymerization of theink.

WO 96/34922, U.S. Pat. No. 5,431,721, and U.S. Pat. No. 5,545,741, 1996respectively describe lithographic inks which employ non-volatilesolvents, but they set by penetration of the non-volatile solvent intothe stock.

U.S. Pat. No. 7,018,453 describes a low VOC web offset heat set inksthat contain a latex polymer. Due to its inherent incompatibility thegloss of printed film is dramatically reduced and at high speed pilingoccurs.

WO 2005/113694 describes an emulsion composition comprising water, ahydrocarbon distillate having a boiling point of 215 to 235° C., and asurfactant having a hydrophilic lipophilic balance number of 10 or less.However, the surfactant described in WO 2005/113694 is monomeric and thestability of the emulsified composition is not very good.

U.S. Pat. No. 5,417,749 describes a printing ink useful for “waterless”printing processes comprising a water-in-oil microemulsion wherein thewater is present in an amount of about 5 to 20 wt. %, based on theweight of the ink. The water phase contains about 0.5 to 3 wt. %, basedon the weight of the ink, of a water soluble surfactant which will notlower the surface tension (as measured at ambient temperature) of theink.

In summary, traditional offset inks have high Volatile Organic Content(VOC) levels. The addition of water to the ink during manufacturing isone way to reduce the VOC level. However, prior attempts to emulsifywater and reduce VOC content has been hampered by poor stability of theemulsified ink. Accordingly, there is a desire to develop bettertechnology to stabilize pre-emulsified water in low VOC web offset heatset and offset inks that have good shelf stability and high dry speed.

SUMMARY OF THE INVENTION

The present invention provides a printing ink comprising:

(a) an emulsion stabilizer having a water tolerance value of betweenmore than about 1.0 and equal or less than about 11.0; and

(b) water as a dispersed phase,

wherein said emulsion stabilizer stabilizes the water to form astabilized emulsion printing ink.

The present invention also provides an emulsion heatset printing inkcomprising;

(a) a VOC content of less than about 35% by weight;

(b) water from about 5 to 50% by weight of the ink; and

(c) an emulsion stabilizer having a water tolerance value of betweenmore than about 1.0 and equal or less than about 11.0,

wherein said ink does not contain a latex polymer.

Other objects and advantages of the present invention will becomeapparent from the following description and appended claims.

DETAILED DESCRIPTION OF THE INVENTION

It has been surprisingly discovered that incorporation of water viamicro emulsions enable reduction of VOCs by up to 50%. The microemulsion was surprisingly achieved with a novel emulsion stabilizerhaving a water tolerance value of between more than about 1.0 and equalor less than about 11.0.

This new class of emulsion stabilizer promotes water-in-oil emulsionstability for pre-emulsified inks, in particular heatset and offsetinks. Preferably, the emulsion stabilizers are prepared by reactingunsaturated oils and/or polymerized/bodied unsaturated oils with maleicanhydride (preferably 4-5 wt. %), and are subsequently reacted,partially or totally, with an amine or alcohol to form an amide orester, respectively.

Preferably, the unsaturated oil and/or polymerized/bodied unsaturatedoil is selected from the group consisting of linseed oil, polymerizedlinseed oil, soy oil, soy fatty acid ester, dehydrated castor fatty acidester. Most preferably, the unsaturated oil is polymerized linseed oil.

Preferably, the amine is selected from the group consisting ofethanolamine, diethylamine, isobutylamine, octyleamine, morpholine,benzylamine and aniline. Also preferably, the alcohol istridecylalcohol.

Preferably, the stabilized emulsion printing ink of the presentinvention comprises water of more than 20% by weight, more preferablyfrom about 5 to about 50% by weight, again more preferably from about 5to about 20% by weight, and most preferably from about 5 to about 15% byweight of the ink.

Also preferably, a printing ink containing the emulsion stabilizer ofthe present invention is a lithographic water-in-oil microemulsionprinting ink having a viscosity between about 30 and about 300 poise andVOC content of less than about 35% by weight, more preferably less thanabout 20% by weight. The amount of emulsion stabilizer present in theprinting ink is preferably less than about 5% by weight, more preferablyfrom about 1 to 3% by weight. Also preferably, the printing ink of thepresent invention does not contain a latex polymer.

The emulsion stabilizer can be produced by the above mentioned procedureprovided that any unsaturated oil or polymerized oil is used and atleast one of the following is used:

1. A secondary monoamine or monoalcohol;

2. A primary monoamine or monoalcohol;

3. A cyclic secondary monoamine is used; or

4. An aromatic primary monoamine or monoalcohol.

The addition of the emulsion stabilizer has another advantage when usedin letterpress inks. Letterpress inks are printed directly onto thepaper, that is, neat inks are applied to the paper. The addition ofwater to the ink will absorb into the paper causing the paper fibers toswell. This swelling of the paper fibers affects the ink/paperinteraction such that the printed image will appear smoother and sharperresembling offset printed inks. The purpose of the emulsion stabilizeris to prevent the water from evaporating as the ink travels along theroller train.

Water Soluble Polymers

The printing ink containing the emulsion stabilizer may optionallycontain a water-soluble polymer. Examples of suitable modified polymerswhich are soluble in the water phase of the ink regardless of the pH ofthe water phase include: carboxymethylcellulose, hydroxyethylcellulose,hydroxypropyl-cellulose, hydroxybutylmethylcellulose, poly(C1, —C4)alkylene oxides, polyethyleneimine, polyvinyl alcohol, polyvinylacetate, polyvinylpyrollidone, polyvinyl-oxazolidone and polyacrylamidepolymers.

Gums is a class of widely used water-soluble polymers. Gums consist ofpolysaccharides with varying polymerization degrees. They include thepolysaccharide hydrocolloids, which are usually prepared from gums, andthey may have been chemically modified, e.g. by partial acetylation, tomake them more water-soluble and/or stable in the presence of the otheringredients in the liquid media. Biopolymers also belonging to thisclass of polysaccharide hydrocolloids. Typical examples of commerciallyavailable, gum-type thickening agents are xanthan gums and theirderivatives. These include a partially acetylated xanthan gum, KELZAN exKelco Company of N.J., USA, SHELLFLO-XA and ENORFLO-XA, xanthan gums exShell Chemicals Ltd., and Rhodapol, a xanthan gum ex Rhone-Poulenc SA.Another example is the biopolymer Shellflo S, a succinoglucan ex ShellChemicals Ltd. Yet other gum-type thickening agents are those derivedfrom guar gums, such as the JAGUAR® products ex Stein, Hall and Co Inc.Further we include Agent AT 2001, Rhodopol 23 and 23 P, Jaguar 8600 and418 which have good solubility in water/solvent mixtures as wellprovided by Rhodia. Other types such as Jaguar 308 NB, Jaguar 2700,Jaguar 8000, Jaguar HP-120 are also included.

A further type of water soluble polymers are METHOCEL and ETHOCELcellulose ether products. These are available in two basic types:methylcellulose and hydroxypropyl methylcellulose. Both METHOCEL typeshave the polymeric backbone of cellulose, a natural carbohydrate thatcontains a basic repeating structure of anhydroglucose units. During themanufacture of cellulose ethers, cellulose fibers are treated withmethyl chloride, yielding the methyl ether of cellulose. These areMETHOCEL A brand products. For hydroxypropyl methylcellulose products(METHOCEL E, F, J, and K brand products), propylene oxide is used inaddition to methyl chloride to obtain hydroxypropyl substitution on theanhydroglucose units. This substituent group, —OCH2CH(OH)CH3-, containsa secondary hydroxyl on the number two carbon and may also be consideredto form a propylene glycol ether of cellulose. These products possessvarying ratios of hydroxypropyl and methyl substitution, a factor whichinfluences organic solubility and the thermal gelation temperature ofaqueous solutions.

ETHOCEL ethylcellulose polymers are derived from and have the polymeric“backbone” of cellulose, which is a naturally occurring polymer. Themolecule has a structure of repeating anhydroglucose units. Note thateach anhydroglucose unit (ring) has three reactive —OH (hydroxyl) sites.Cellulose is treated with an alkaline solution to produce alkalicellulose, which is subsequently reacted with ethyl chloride, yieldingcrude ethylcellulose. Specific properties of the various ETHOCELpolymers are determined by the number of anhydroglucose units in thepolymer chain and the degree of ethoxyl substitution.

CELLOSIZE HEC polymers are named after their two components: celluloseand hydroxyethyl side chains. Cellulose itself is a water-insoluble,long-chain molecule consisting of repeating anhydroglucose units. In themanufacture of CELLOSIZE HEC, a purified cellulose is reacted withsodium hydroxide to produce a swollen alkali cellulose. Thisalkali-treated cellulose is more chemically reactive than cellulose. Byreacting the alkali cellulose with ethylene oxide, a series ofhydroxyethyl cellulose ethers is produced. In this reaction, thehydrogen atoms in the hydroxyl groups of cellulose are replaced byhydroxyethyl groups, which confer water solubility to the product.

Finally another group of well-known, suitable organic polymers, includeacrylate homo- or copolymers and derivatives thereof. Typical examplesof such materials which are suitably cross-linked are the acryliccopolymers sold by National Starch and Chemical Ltd under the tradenames EP 1910 and PPE 1042 or Ultrasperse Starches. Other types of such(meth)acrylic homo- and copolymers are certain Carbopol®-type,cross-linked carboxyvinyl polymers such as CARBOPOL®-940 ex B. F.Goodrich Co Ltd. Other examples are the Viscalex products ex AlliedColloids, which are emulsions of (meth)acrylic acid copolymers with(meth)acrylate esters, e.g. VISCALEX HV 30, ACRYSOLS (ex Rohm & Haas)and UBATOLS (ex Stapol).

Evaluation of Emulsion Stabilizers by Shearing Followed by VisualAssessment Overtime

The emulsion stabilizers or non-water soluble polymeric surfactants ofthe present invention were evaluated by shearing a weighed quantity ofthe emulsion stabilizer in a jar using a mixer at high speed. A weighedquantity of water was then pipetted into the mixing solution and furthersheared for 10 minutes. The emulsion was than transferred into a vialand capped. A visual assessment is made periodically for water/oilseparation and color. The ratings of these sheared/mixed emulsions werebased on whether the emulsion is stable for a least one week and thecolor. A whitish color has been determined to be more desirable due tothe smaller particle size which provides a more stable emulsion. Anemulsion stabilizer is classified as excellent if there is no separationof the emulsion after one week and is white in color. An emulsionstabilizer is classified as good if there is no separation of theemulsion after one week and is tan or brown in color. An emulsionstabilizer is classified as acceptable if there is no separation of theemulsion after 3-5 days. Any separation that takes place in less than 3days is considered poor.

Testing of Emulsified Ink Using Microscope

Emulsified ink (5 mg) was put on a slide glass, and another slide glasswas piled on it. The ink was observed at a magnifying power of 450 anddrops of water may be observed.

Maximum diameter of drops is ^(X)not acceptable more than 13 micrometerMaximum diameter of drops is Δacceptable between 5 and 13 micrometerMaximum diameter of drops is ^(◯)good less than 5 micrometer Almost nodrops in the ink ⊚excellentTesting of Emulsified Ink Using Hoover Muller

Emulsified ink (1.0 g) was put on a Hoover Muller. At a weight of 1.1kilogram, ink was milled for 100 rotations. Milled ink was scraped witha ink knife and the ink was observed as follows:

A lot of water is separated ^(X)not acceptable Small drops of water areseen Δacceptable Almost no drops of water are seen ^(◯)goodMethod of Measuring Water Tolerance Value of Emulsion Stabilizer(Emulsifier)

Emulsifier (0.5 g) was dissolved in 10 ml of THF, and put in 50 mlbeaker. Water was dropped in the beaker until the solution becomescloudy. Water tolerance is the weight of water dropped when the solutionbecomes cloudy. Large water tolerance means that the emulsifier is morehydrophilic.

Example 1 Preparation and Testing of Emulsion Stabilizer 1-1

Polymerized linseed oil (86.1 parts) was charged into a four-neck roundbottom flask and heated to 205° C. under a nitrogen blanket. To this,maleic anhydride (4.1 parts) was added. This mixture was held for onehour. After one hour a sample of the mixture was withdrawn from theflask and placed on a glass plate with white paper under it. To thissample, 2 drops of N,N-dimethylaniline were added. The sample andN,N-dimethylaniline were mixed. When a red color appeared, free maleicanhydride was present and the reaction was further held. When there wasno color change, the reaction proceeded to the next step.

The batch was then cooled to 120° C. and diethylamine (9.8 parts) wasadded over 90 minutes and held for one hour after the addition. Afterthe one hour hold, the temperature was raised to 205° C. The batch washeld at this temperature until there is a zero amine value and an acidvalue of 23-27. When the amine value was zero and the acid value 23-27,the batch was cooled to 140° C., then discharged. The water tolerancevalue of the emulsion stabilizer produced was measured as indicatedhereinabove at 1.1.

The emulsion stabilizer prepared was evaluated by shearing a weighedquantity of the emulsion stabilizer in a jar using a mixer at high speedas described above. It produced good to excellent stable emulsions.

Example 2 Preparation and Testing of Emulsion Stabilizer 2-1

Polymerized linseed oil (90.4 parts) was charged into a four-neck roundbottom flask and heated to 205° C. under a nitrogen blanket. To this,maleic anhydride (4.1 parts) was added. This mixture was held for onehour. After one hour a sample of the mixture was withdrawn from theflask and placed on a glass plate with white paper under it. To thissample, 2 drops of N,N-dimethylaniline were added. The sample andN,N-dimethylaniline was mixed. When a red color appeared, free maleicanhydride was present and the reaction was further held. When there wasno color change, the reaction proceeded to the next step.

The batch was then cooled to 120° C. At 120° C., isobutylamine (5.5parts) was added over 90 minutes and held for one hour after theaddition. After the one hour hold, the temperature was raised to 205° C.The batch was held at this temperature until there was a zero aminevalue and an acid value of 23-27. When the amine value was zero and theacid value 23-27, the batch was cooled to 140° C., then discharged. Thewater tolerance value of the emulsion stabilizer produced was measuredas indicated hereinabove at 1.3.

The emulsion stabilizer prepared was evaluated by shearing a weighedquantity of the emulsion stabilizer in a jar using a mixer at high speedas described above. It produced good to excellent stable emulsions.

Example 3 Preparation and Testing of Emulsion Stabilizer 3-1

Polymerized linseed oil (91.7 parts) was charged into a four-neck roundbottom flask and heated to 205° C. under a nitrogen blanket. To this,maleic anhydride (4.3 parts) was added. This mixture was held for onehour. After one hour a sample of the mixture was withdrawn from theflask and placed on a glass plate with white paper under it. To thissample, 2 drops of N,N-dimethylaniline were added. The sample andN,N-dimethylaniline were mixed. When a red color appeared, free maleicanhydride was present and the reaction was further held. When there wasno color change, the reaction proceeded to the next step.

The batch was then cooled to 120° C. At 120° C., morpholine (4.0 parts)was added over 90 minutes and held for one hour after the addition.After the one hour hold, the temperature was raised to 205° C. The batchwas held at this temperature until there is a zero amine value and anacid value of 23-27. When the amine value reached zero and the acidvalue 23-27, the batch was cooled to 140° C., then discharged. The watertolerance value of the emulsion stabilizer produced was measured asindicated hereinabove at 1.3.

The emulsion stabilizer prepared was evaluated by shearing a weighedquantity of the emulsion stabilizer in a jar using a mixer at high speedas described above. It produced good to excellent stable emulsions.

Example 4 Preparation and Testing of Emulsion Stabilizer 4-1

Polymerized linseed oil (90.4 parts) was charged into a four-neck roundbottom flask and heated to 205° C. under a nitrogen blanket. To this,maleic anhydride (4.1 parts) was added. This mixture was held for onehour. After one hour a sample of the mixture was withdrawn from theflask and placed on a glass plate with white paper under it. To thissample, 2 drops of N,N-dimethylaniline were added. The sample andN,N-dimethylaniline were mixed. When a red color appeared, free maleicanhydride was present and the reaction was further held. When there wasno color change, the reaction proceeded to the next step.

The batch was cooled to 120° C. At 120° C., diethylamine (5.5 parts) wasadded over 90 minutes and held for one hour after the addition. Afterthe one hour hold, the temperature was raised to 205° C. The batch washeld at this temperature until there was a zero amine value and an acidvalue of 23-27. When the amine value was zero and the acid value is23-27, the batch was cooled to 140° C., then discharged. The watertolerance value of the emulsion stabilizer produced was measured asindicated hereinabove at 1.2.

The emulsion stabilizer prepared was evaluated by shearing a weighedquantity of the emulsion stabilizer in a jar using a mixer at high speedas described above. It produced good to excellent stable emulsions. Inaddition, it has been field trialed in an ink and found to work quitewell.

Example 5 (1) Preparation of Emulsion Stabilizers 5-1 to 5-34

Emulsion Stabilizers 5-1, 5-2 and 5-34

Emulsion stabilizer 5-1 is a commercial surfactant (Kao Corporation).Emulsion stabilizer 5-2 is a commercial surfactant (DAI-ICHI KOGYOSEIYAKU CO., LTD.). Emulsion Stabilizer 5-34 is a soybean isophtalicalkyd (DAINIPPON INK AND CHEMICALS, INCORPORATED).

Emulsion Stabilizers 5-3 to 5-26, 5-28 to 5-33

Emulsion Stabilizers 5-3 to 5-26, 5-32 and 5-33 were made by the samesynthetic method as described in Example 3. The emulsion stabilizers,numbered 5-28 to 5-31, were made from monglyceride and diglyceride. Theamines or alcohol were charged in the flask below their boiling point.The target of each acid value is shown in Table 2.

Emulsion Stabilizer 5-27

Linseed oil (70 parts) and polyoxyethylene-trimethylpropane ether (24parts) were charged into a four-neck round bottom flask and heated to220° C. This mixture is made to react to the five or less acid value.After the acid value was measured at five or less, the batch was thencooled to 160° C. To this, maleic anhydride (3 parts) was added. Thismixture was held for one hour. After one hour a sample of the mixturewas withdraw from the flask and placed on a glass plate with white paperunder it. To this sample, 2 drops of N,N-dimethylaniline were added. Thesample and N,N-dimethylaniline were mixed. When a red color appeared,free maleic anhydride was present and the reaction was further held.When there was no color change, the reaction proceeded to the next step.

The batch was then cooled to 120° C. At 120° C., morpholine (3 parts)was added over 90 minutes and held for one hour after the addition.After the one hour hold, the temperature was raised to 205° C. The batchwas held at this temperature until there is zero amine value and an acidvalue of 12-16. When the amine value reached zero and the acid value12-16, the batch was cooled to 140° C., then discharged.

Emulsion Stabilizer 5-28

Linseed oil (76 parts) and glycerol (4 parts) were charged into afour-neck round bottom flask and heated to 240° C. This mixture was keptat 240° C. for 2 hours to exchange the ester with catalyst. After theester exchange, the batch, which was diglyceride, was cooled to 160° C.To this, maleic anhydride (14 parts) was added. This mixture was heldfor one hour. After one hour a sample of the mixture was withdraw fromthe flask and placed on a glass plate with white paper under it. To thissample, 2 drops of N,N-dimethylaniline were added. The sample andN,N-dimethylaniline were mixed. When a red color appeared, free maleicanhydride was present and the reaction was further held. When there wasno color change, the reaction proceeded to the next step.

The batch was then cooled to 120° C. At 120° C., morpholine (6 parts)was added over 90 minutes and held for one hour after the addition.After the one hour hold, the temperature was raised to 205° C. The batchwas held at this temperature until there is zero amine value and an acidvalue of 31-35. When the amine value reached zero and the acid value31-35, the batch was cooled to 140° C., then discharged.

Emulsion Stabilizer 5-29

Linseed oil (43 parts) and glycerol (9 parts) were charged into afour-neck round bottom flask and heated to 240° C. This mixture was keptat 240° C. for 2 hours to exchange the ester with catalyst. After theester exchange, the batch, which was mono-glyceride, was cooled to 160°C. To this, maleic anhydride (30 parts) was added. This mixture was heldfor one hour. After one hour a sample of the mixture was withdraw fromthe flask and placed on a glass plate with white paper under it. To thissample, 2 drops of N,N-dimethylaniline were added. The sample andN,N-dimethylaniline were mixed. When a red color appeared, free maleicanhydride was present and the reaction was further held. When there wasno color change, the reaction proceeded to the next step.

The batch was then cooled to 120° C. At 120° C., morpholine (18 parts)was added over 90 minutes and held for one hour after the addition.After the one hour hold, the temperature was raised to 205° C. The batchwas held at this temperature until there was zero amine value and anacid value of 43-47. When the amine value reached zero and the acidvalue 43-47, the batch was cooled to 140° C., then discharged.

Table 1 describes the identity of the emulsion stabilizer as well as theingredients used in preparing said emulsion stabilizers.

TABLE 1 Reactive Point Oil Type MA n/oil wt Amine or Alcohol wt % wt.ratio % wt % Emulsion 5-1  RO(CH₂CH₂O)nH Polyoxyethylene glycol etherstabilizer 5-2  Polyoxyethylene(20) sorbitan monooleate Emulsion 3-1 Polymerized 91.7 Maleic (MA n/oil)* 4.3 Morpholine 4.0 StabilizerLinseed Oil anhydride (Poly LO) (MA n) 5-3  Varnish No. 3 92 (MA n/oil)*× 0.9 4 4 5-4  (Poly LO) 88 (MA n/oil)* × 1.0 4 8 5-5  93 (MA n/oil)* ×0.9 4 Ethanolamine 3 5-6  94 (MA n/oil)* × 0.7 3 Morpholine 3 5-7  96(MA n/oil)* × 0.4 2 2 5-8  98 (MA n/oil)* × 0.0 0 2 5-9  Varnish No. 492 (MA n/oil)* × 0.9 4 4 (Poly LO) 5-10 Varnish No. 5 92 4 4 (Poly LO)5-11 Varnish No. 6 92 4 4 (Poly LO) 5-12 Varnish No. 7 92 4 4 (Poly LO)5-13 Linseed Oil 92 4 4 5-14 (LO) 80 (MA n/oil)* × 2.9 11 9 5-15 72 (MAn/oil)* × 4.4 15 13 5-16 56 (MA n/oil)* × 7.2 19 25 5-17 91 (MA n/oil)*× 0.9 4 Benzylamine 5 5-18 93 4 Ethanolamine 3 5-19 Soybean Oil 92 4Morpholine 4 5-20 Varnish No. 6 54 (MA n/oil)* × 7.1 18 28 (Poly LO)5-21 Linseed Oil 49 (MA n/oil)* × 9.6 22 29 5-22 Linseed Oil 44 (MAn/oil)* × 11.6 24 32 5-23 Linseed Oil 51 (MA n/oil)* × 7.1 17Laurylamine 32 5-24 44 (MA n/oil)* × 7.3 15 Stearylamine 41 5-25 58 (MAn/oil)* × 7.0 19 Morpholine 12 FARMIN 20D 11 5-26 95 (MA n/oil)* × 0.4 2Morpholine 3 5-27 LO 94 — 3 3 EthyleneOxide ester 5-28 LO diglyceride 80— 14 6 5-29 LO 52 — 30 18 5-30 monoglyceride 51 — 30 19 5-31 51 — 29 205-32 Varnish No. 3 90 (MA n/oil)* × 0.9 4 Dibutylamine 6 (Poly LO) 5-33Varnish No. 6 87 (MA n/oil)* × 1.0 4 Tridecylalchol 9 (Poly LO) 5-34Soybaen Isophtalic Alkyd 5-35 Polymerized Linseed Oil 5-36 No Surfactant*MAn/oil wt. ratio means the weight ratio of maleic anhydride tounsaturated-/polymerized/bodied oil. Values for MAn/oil wt are indicatedas Xvalue which are multiples of the standard value for Emulsionstabilizer 3-1. For the standard emulsion stabilizer 3-1, polymerizedlinseed oil(poly LO) is 91.7 wt %, and maleic anhydride(MAn) is 4.3 wt%. Accordingly, the MAn/oil is 4.3/91.7(=0.0469), and it is specified as(MAn/oil)*.

(2) Preparation of Emulsified Inks

Emulsified ink formulations were prepared containing an emulsionstabilizer as described in Table 1 and other components as follows:

Standard web offset ink 94 parts (Web world New Advan yellow (N type))emulsion stabilizer (see Table 1) 1 part water 5 parts

The total parts of each ink formulation was mixed well by usinglaboratory mixer at 6000 rpm for 10 minutes, and emulsified ink wasobtained.

Table 2 shows the testing results of emulsified inks using microscopeand Hoover Muller tests as described previously. Table 2 also containsthe results of water tolerance testing of each emulsion stabilizer asdescribed previously.

TABLE 2 Hoover Muller targeted Microscope Water acid Water Water Separa-value tolerance Size Result tion Emulsion 5-1  — 13.9 6.3 Δ X Stabilizer5-2  — 11.2 4.8 ◯ X Emulsion 3-1  23-27 1.3 Invisible ⊚ Δ Stabilizer5-3  29-33 1.4 8.3 Δ ◯ 5-4  22-26 1.8 10.0 Δ ◯ 5-5  20-24 1.3 5.0 Δ Δ5-6  23-27 1.2 5.1 Δ ◯ 5-7  17-21 1.2 9.1 Δ ◯ 5-8   8-12 1.1 12.2 Δ ◯5-9  27-31 1.5 Invisible ⊚ ◯ 5-10 26-30 1.6 8.4 Δ ◯ 5-11 22-26 1.7 8.7 Δ◯ 5-12 20-24 2.2 3.3 ◯ ◯ 5-13 16-20 2.4 2.2 ◯ ◯ 5-14 42-46 2.7 7.3 Δ ◯5-15 51-55 3.4 6.1 Δ ◯ 5-16 59-63 6.9 2.2 ◯ ◯ 5-17 21-25 2.2 13.0 Δ ◯5-18 15-19 2.4 11.1 Δ ◯ 5-19 17-21 2.2 12.2 Δ ◯ 5-20 31-35 7.9 5.5 Δ Δ5-21 58-62 9.8 4.2 ◯ ◯ 5-22 62-66 10.8 3.9 ◯ ◯ 5-23 21-25 2.0 3.3 Δ ◯5-24 20-24 1.4 2.4 ◯ ◯ 5-25 55-59 2.9 2.8 ◯ ◯ 5-26  7-11 2.2 4.4 ◯ ◯5-27 12-16 2.3 8.1 Δ Δ 5-28 31-35 2.5 5.3 Δ Δ 5-29 43-47 3.3 6.7 Δ ◯5-30 30-34 3.5 4.0 ◯ ◯ 5-31 29-33 3.6 9.7 Δ Δ 5-32 25-29 1.0 9.3 Δ ◯5-33 29-33 1.1 7.3 Δ Δ 5-34 — 0.9 6.3 Δ X 5-35 — 0.9 16.3 X X 5-36 — —16~20 X X

As indicated hereinabove, water size by microscope indicates the degreeof emulsification. The smaller the water size is, the more the water isfinely emulsified in ink. Table 2 shows that emulsion stabilizers with awater tolerance value in the claimed range make the water size smalleran allow for passing of the Hover Muller water separation test.

The invention has been described in terms of preferred embodimentsthereof, but is more broadly applicable as will be understood by thoseskilled in the art. The scope of the invention is only limited by thefollowing claims.

1. A printing ink comprising: (a) an emulsion stabilizer having a watertolerance value of between more than about 1.0 and equal or less thanabout 11.0, said emulsion stabilizer present in the printing ink fromabout 1 to 3% by weight; (b) water as a dispersed phase, wherein saidemulsion stabilizer stabilizes the water to form a stabilized emulsionprinting ink; (c) a water soluble polymer, and (d) a VOC content of lessthan about 35% by weight.
 2. The printing ink of claim 1, wherein saidwater phase is from about 5 to 50% by weight of the ink.
 3. The printingink of claim 1, wherein said water phase is from about 5 to 20% byweight of the ink.
 4. The printing ink of claim 1, wherein said waterphase is from about 10 to 15% by weight of the ink.
 5. The printing inkof claim 1, wherein said emulsion stabilizer is prepared by reacting anunsaturated oil and/or polymerized/bodied unsaturated oil with maleicanhydride followed by a further partial or complete reaction with anamine to form an amide.
 6. The printing ink of claim 1, wherein saidemulsion stabilizer is made by reacting unsaturated oil and/orpolymerized/bodied unsaturated oil with maleic anhydride followed by afurther partial or complete reaction with an alcohol to form an ester.7. An emulsion heatset printing ink comprising; (a) a VOC content ofless than about 35% by weight; (b) water from about 5 to 50% by weightof the ink; (c) a water soluble polymer, and (d) an emulsion stabilizerhaving a water tolerance value of between more than about 1.0 and equalor less than about 11.0, said emulsion stabilizer present in theprinting ink from about 1 to 3% by weight of the ink, wherein said inkdoes not contain a latex polymer.
 8. The printing ink of claim 7 being alithographic printing ink.
 9. The printing ink of claim 7, wherein saidVOC content is less than about 15% by weight of the ink.
 10. Theprinting ink of claim 7, wherein said VOC content is less than about 10%by weight of the ink.
 11. The printing ink of claim 7, wherein said VOCcontent is less than about 5% by weight of the ink.
 12. The printing inkof claim 7 being a water-in-oil microemulsion printing ink.
 13. Theprinting ink of claim 7 having a viscosity between about 30 and about300 poise.
 14. The printing ink of claim 7, wherein said emulsionstabilizer is prepared by reacting an unsaturated oil and/orpolymerized/bodied unsaturated oil with maleic anhydride followed by afurther partial or complete reaction with an amine to form an amide. 15.The printing ink of claim 7, wherein said emulsion stabilizer is made byreacting unsaturated oil and/or polymerized/bodied unsaturated oil withmaleic anhydride followed by a further partial or complete reaction withan alcohol to form an ester.